Lamp holder



way-

1957 c. H. J. ANDERSON 2,802,999

LAMP HOLDER Filed April 4, 1955 7 7 1&- 13 8 5 8 1 1 l l A r "I H19 CHABLE S HENRI JOSEPH ANDERSON INVENTOP AGE T United States Parent 0.

LAMP HOLDER .Charles Henri Joseph Anderson, Eindhoven, Netherlands, assignorfby 'mesn'e assignments, to North American Philips Gompany, -Inc.,'New-York, N.fi., a corporation of Delaware Application April 4, 1955, Serial No. 499,170

Claims priority, application Netherlands April 2, 1954 2 Claims. (Cl. 339-188) This invention relates to improvements in lamp holders and more particularly to lamp holders being provided with ceramic sockets therein.

One of the difiiculties in producing ceramic sockets for lamp holders lies in the fact that the ceramic material shrinks unevenly during the molding process. Consequently, reproducible results cannot be achieved and in cases where precision lamp holders are desired known lamp constructions using ceramic sockets have been unsuccessful unless additional and complicated adjusting devices are used.

A principal object of this invention is to provide a construction for a lamp holder using a ceramic socket in which reproducible results may be achieved for uses including precision lamp holders.

The above and other features, objects and advantages of the present invention will be fully understood from the following description considered in connection with the accompanying illustrative drawing in which:

Fig. 1 is a sectional view of a lamp holder in accordance with the invention, and

Fig. 2 is a plan view of the holder shown in Fig. 1.

In the drawing, reference numeral 1 designates the socket of a lamp holder which has a substantially cylindrical form. The lamp holder is provided with two flanges 2 and 3, each of which has an aperture 4 and 5 respectively. The housing can be secured to support 6 by means of bolts inserted in apertures 4 and 5. Surfaces 7 and 8 of flanges 2 and 3 serve as supporting surfaces.

A metal sleeve-shaped body 9 is inserted in and secured to the bottom portion 12 of the housing by means of bolts 10, one of which has a contact piece 11 secured to it. The top of the sleeve 9 has a flange 13, which projects outwardly and connects with a cylindrical part 14. An annular body 17 is clamped on the cylindrical part 14 of sleeve 9. The lower part of annular body 17 has a flange 16 which engages flange 13 and is supported by seating surface located on the inner wall of the socket. The top of the annular body 17 has two circular segment shaped recesses 19 and 20.

A central contact 21, which is subjected to the action of the locked pressure spring 22 is located in the bottom of housing 12. This central contact is provided with a contact block 23.

The lamp associated with this holder (not shown) is provided with a cylindrical lamp cap having a central contact in the bottom and a second contact on the sheath of the cap. A ring having two wing-shaped members projecting sideways therefrom is secured to this sheath. When manufacturing this lamp, the top surfaces of these wings are accurately adjusted relative to the filament body in the lamp. When inserting this lamp into the holder shown, the lamp must be positioned over the holder in a manner such that the wings of the cap lie over the recesses 19 and 20 in the flange 18. If the lamp is moved downwards into the lamp holder, the central contact of the cap bottom will engage the central contact 21 of the holder. The lamp must be moved downwards so that :the :wings 40f the lamp are lower than the flange 118 of :Fig. :1. lfithe lamp is then turned through a given angle about-tits taxis oflength, the'wings will be positioned'below Lthefiange s18. lfithelamp is released, the resilientcentral -contacti21 of the holder'urges the upper-surfaces of;these .wings against the bottom surface of flange 1'8. Thus,-a predetermined position of the filament :body 1 in the lamp :relative "to the flange .18 is obtained. Because of 'the presence ofthesmetal in s'leeve-shaped body 9, :thefla-nge 18 occupies a stationary position relative to the fitting edge 15 of the holder. In accordance with the invention it has been found that when the distance between the seating surface 15 and at least one of the supporting surfaces on the outer wall of the holder is small, i. e., not greater than 15 mm. measured in the axial direction of the holder, the non-reproducible shrinkage of the material of the socket of the holder is not troublesome. In the embodiment shown the seating surface 15 on the inner side of the housing of the holder and the supporting surface 8, by means of which the holder is secured to the plate-shaped support, substantially coincide. In the embodiment shown the bottom surface 24 of flanges 2 and 3 could be used as a supporting surface. As an alternative, flanges 2 and 3 of the drawing may include thickened portions 25 and 26 (shown in broken lines), in which case the top surfaces 7 and 8 of these thickened portions serve as supporting surfaces. The supporting surface may, of course, be constituted also by a continuous edge around the holder.

In the embodiment of the holder according to the invention as shown in the drawing, the bottom surface 27 of the metal sleeve-shaped part 9 bears on the inner surface of the bottom 12 of the socket of the holder. However, a further embodiment of the holder may, in the baked condition, have a dimension a between the seating surface 15 and the upper surface of the bottom 12 which is slightly larger than in the embodiment shown. In this case the bottom surface of the bottom part 27 of the sleeve is spaced from the top surface of the bottom 12 of the socket of the holder, this difference in distance being compensated by adjustment of the fastening bolt 10 in the contact piece 11. In spite of these differences in the dimension a, the distance between the supporting surface and the seating surface in different sockets of the same series remains substantially the same, so that in this manner lamp holders having sockets with variations in tolerance may be obtained and accordingly used as a precision lamp holder.

While I have shown and described the preferred embodiment of my invention, it will be understood that the latter may be embodied otherwise than as herein specifically illustrated or described and that in the illustrated embodiment certain changes in the details of construction and in the arrangement of parts may be made without departing from the underlying idea or principle of the invention within the scope of the appended claims.

What is claimed is:

1. A lamp holder for supporting a lamp having a plurality of flanged adjusting members thereon comprising a support, a ceramic socket having a counterbore on the inner wall thereof adjacent to the open end thereof, a hollow annular metallic body supported by said counterbore, a metal sleeve in said ceramic socket having a portion engaged by said annular metallic body, means se curing said metal sleeve to said ceramic socket said annular body being provided with slots for the insertion of the flanged adjusting members of said lamp therethrough, a biasing means mounted in the lower portion of the socket to urge the adjusting members against the annular body, a planar mounting surface on the outer wall of the socket for mounting said holder to said support, the distance between said seating surface and said supporting surface measured in the axial direction of the socket being no greater than 15 mm.

2. A lamp holder for supporting a lamp having a plurality of flanged adjusting members thereon comprising a support,.a ceramic socket having a counterbore on :the

innerwall thereof adjacent to the open end thereof, a hollow annular metallic body mounted on said counterbore, an adjustable metal sleeve secured in said socket engaging and urging said annular body against said counterbore, said annular body being provided with slots for the insertion of the flanged adjusting members of said lamp therethrough, a spring-urged contact mounted in the lower portion of the socket to urge the adjusting l 4 members of the lamp against the annular body, a planar mounting surface on the outer, wall of the socket for mounting said holder to said support, the mounting surface and the bottom of said counterbore being in substantially parallel planes.

References Cited in the file of this patent UNITED STATES PATENTS 

